Alignment layer for a liquid crystal display device

ABSTRACT

The liquid crystal display device of the present invention comprises first and second substrates; a first alignment layer on the first substrate, wherein the first alignment layer includes                  
 
(spacer S is oxygen, m=10˜10,000), the functional group R includes photo-sensitive constituents and/or non-photo-sensitive constituents, the photo-sensitive constituent includes a material selected from the group consisting of cinnamoyl derivatives, the non-photo-sensitive constituent includes a material selected from the group consisting of C n H 2n , C n H 2n+1 , C n H 2n OH, COC n H 2n+1 , COC n H 2n , C n H 2n+1−x F x , C n H 2n−(x−1) F (x−1) , C n H 2n−x F x OH, COC n H 2n+1−x F x  (n=1˜10, x=1˜2n+1), and a combination thereof; and a liquid crystal layer between the first and second substrates.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No.: 09/534,723 filed Mar. 24, 2000, now U.S. Pat. No. 6,764,724;which claims priority to Korean Patent Application No. 1999-10214, filedMar. 25, 1999, each of which is incorporated by reference for allpurposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an alignment layer, and moreparticularly to an alignment layer with photo-sensitivity.

2. Description of the Related Art

It is generally known that a liquid crystal consists of anisotropicmolecules. The average direction of the long axes of the id crystalmolecules is called the director of the liquid crystal. The directordistribution in a liquid crystal is determined by the anchoring energyon a substrate, and is characterized by a director corresponding to aminimum of the surface energy of the liquid crystal and the anchoringenergy. The director is rearranged by an electric field generated duringoperation of a liquid crystal display device (LCD). An LCD comprises twoopposed substrates having liquid crystal therebetween.

In general, to obtain uniform brightness and a high contrast ratio, itis necessary to align the liquid crystal molecules uniformly in a liquidcrystal cell. Several techniques have been proposed using polymers toobtain single or mono-domain homogeneous alignment of liquid crystals.Particularly, it is known that polyimide or polysiloxane-based materialshave high quality and good thermostability.

The most common technique employed as an alignment method to obtain amono-domain liquid crystal cell involves forming microgrooves on thesurface of the alignment polymer, which provides strong anchoring andstable alignment. In the above-mentioned technique, known as the rubbingmethod, a substrate coated with an alignment polymer is rubbed with acloth. The rubbing method is a good method which can be applied to largescale LCDs, and thus is widely used in the industry.

The rubbing method, however, has several serious drawbacks. Because theshape of the microgrooves formed on the alignment layer depends on therubbing cloth and rubbing intensity, the resulting alignment of theliquid crystal is often heterogeneous, causing phase distortion andlight scattering. Further, electrostatic discharge (ESD) generated byrubbing of the polymer surface further generates dust contamination inan active matrix LCD panel, decreasing production yield and damaging thesubstrate.

In order to solve these problems, a photo-alignment method has beenproposed using polarized ultraviolet light irradiated onto aphotosensitive polymer to photo-polymerize the polymer (A. Dyadyusha, V.Kozenkov et al., Ukr. Fiz. Zhurn., 36 (1991) 1059; W. M. Gibbons et al.,Nature, 351 (1991) 49; M. Schadt et al., Jpn. J. Appl. Phys., 31 (1992)2155; T. Ya. Marusii & Yu. A. Reznikov, Mol. Mat., 3 (1993) 161; EP0525478; and U.S. Pat. No. 5,538,823—a polyvinyl-fluoro cinnamatepatent). The alignment capability of the photosensitive polymer isdetermined by the anisotropy of the photosensitive polymer, which isinduced by ultraviolet light irradiation.

In the photo-alignment method, an alignment layer is given an alignmentdirection by irradiating a substrate coated with a photo-alignmentmaterial with linearly polarized UV light. The photo-alignment layercomprises a polyvinyl cinnamate-based (PVCN) polymer, and as linearlypolarized UV light is irradiated, the polymer photo-polymerizes throughcross-linking. Cross-linking is generated among the polymers by the UVlight energy.

The alignment direction of the photo-alignment layer has a specificdirection in relation to the polymerization direction of the linearlypolarized UV light. The alignment direction of the photo-alignment layeris determined by the direction of the photo-polymers. The pretilt angleof the photo-alignment layer is determined by the incident direction andthe irradiating energy of the irradiated UV light. That is to say, thepretilt angle direction and the pretilt angle of the photo-alignmentlayer are determined by the polarized direction and the irradiatingenergy of the irradiated UV light.

With regard to photo-alignment, a polarizer is rotated at an arbitraryangle on each domain of the LCD. Then, in response to irradiating UVlight, the polarization direction is changed, whereby a multi-domain LCDcell is achieved with multiple domains having different alignmentdirections in relation to each other.

The photo-alignment method, however, has several drawbacks. For example,it is impossible to apply on a wide scope. Most importantly, lowphoto-sensitivity of the photo-alignment material results in reductionof anisotropy and thermostability.

UV light irradiation takes a long time using conventional techniques,from approximately 5 to as long as 10 minutes. Low photo-sensitivity andsmall anisotropy make the anchoring energy of the final photo-alignmentlayer weak. Moreover, when the liquid crystal is injected into theliquid crystal panel, it is required that the injection be made at ahigh temperature. Low thermostability induces a flowing effect on thesubstrates, which can be observed as a ripple pattern in the liquidcrystal upon injection between the substrates. Finally, disclinationowing to the non-uniform alignment of liquid crystals remains as aproblem to be solved.

SUMMARY OF THE PREFERRED EMBODIMENTS

Accordingly, the present invention is directed to a LCD thatsubstantially obviates one or more of the problems due to limitationsand disadvantages of the related art.

An object of the present invention is to provide an LCD having goodthermostability and photo-sensitivity.

Another object of the present invention is to provide an alignment layerhaving good stability and pretilt angles which are easily controlled,which results from inserting a spacer such as a polyoxomethyl groupbetween the main chain and the functional group including cinnamolyderivatives in a CelCN photo-aligning material.

Hydroxyethyl cellulosecinnamate (HE-CelCN) of the present invention hasa strong anchoring energy, good photo-sensitivity, adhesive strength,and high thermostability so that it could provide an excellent andstable alignment.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, theliquid crystal display device of the present invention comprises firstand second substrates; a first alignment layer on the first substrate,wherein the first alignment layer includes

(spacer S is oxygen, m=10˜10,000), the functional group R includes atleast one of a group consisting of photo-sensitive constituents andnon-photo-sensitive constituents, the photo-sensitive constituentsinclude a material selected from the group consisting of cinnamoylderivatives, the non-photo-sensitive constituents include a materialselected from the group consisting of C_(n)H_(2n), C_(n)H_(2n+1),C_(n)H_(2n)OH, COC_(n)H_(2n+1), COC_(n)H_(2n), C_(n)H_(2n+1−x)F_(x),C_(n)H_(2n−(x−1))F_((x−1)), C_(n)H_(2n−x)F_(x)OH, COC_(n)H_(2n+1−x)F_(x)(n=1˜10, x=1˜2n+1), and a combination thereof; and a liquid crystallayer between the first and second substrates.

The liquid crystal display device of the present invention preferablycomprises a second alignment layer on the second substrate. The secondalignment layer includes a material selected from the group consistingof a pyranose polymer, a furanose polymer, polyvinyl cinnamate,polysiloxane cinnamate, polyvinyl alcohol, polyamide, polyimide,polyamic acid and silicone dioxide.

The cinnamoyl derivative includes at least one member selected from thegroup consisting of hydrogen, fluorine, chlorine, cyano, NO₂, CH₃, OCH₃,CF₃, OCF₃, C_(n)H_(2n+1), OC_(n)H_(2n+1), C₆H₅, C₆H₄OC_(n)H_(2n+1),C_(n)H_(2n+1−x)F_(x), OC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1).

Alternatively, the cinnamoyl derivative is

(X₁ X₂ are each selected from the group consisting of hydrogen,fluorine, chlorine, CN, NO₂, CH₃, OCH₃, CF₃, OCF₃; k is 0 to 1; Y isselected from the group consisting of hydrogen, fluorine, chlorine,cyano, NO₂, CF₃, OCF₃, C_(n)H_(2n+1), OC_(n)H_(2n+1),C_(n)H_(2n+1−x)F_(x), OC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1)).

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawing, in which:

FIG. 1 illustrates a liquid crystal display (LCD) device according toone or more aspects of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention.

In order to enhance the sensitivity of a photo-alignment layer for aliquid crystal device and obtain thermostable anchoring of the liquidcrystal, cellulose cinnamate (CelCN) consisting of a main chain andhydroxyethyl group between functional groups is used as thephoto-alignment material. Several different forms of hydroxyethylcellulose cinnamate (HE-CelCN) suitable for hydroxyethyl cellulose andcinnamoyl chloride having various substitution ratios.

A cinnamic acid is first prepared by reacting a benzaldehyde withmalonic acid in pyridine and piperidine. The cinnamic acid is thenreacted with thionyl chloride to produce a cinnamoyl chloridederivative. The HE-CelCN is finally synthesized by reacting HE-cellulosewith the cinnamoyl chloride derivative in an inert solvent (such aschloroform, nitrobenzene, chlorobenzene, or the like). The reactionmixture is diluted with methanol, filtered, dried in a vacuum, andmilled by a vibrating mill, whereupon the CelCN is obtained.

A process of forming an alignment layer according to an embodiment ofthe present invention comprises the following three steps.

First, a polymer solution is prepared using dichloroethane as a solvent.The concentration of the polymer determines the ultimate thickness ofthe alignment layer on the LCD substrates. To form a film having athickness of approximately 1 μm, HE-CelCN solution of 10 g/l is selectedfor coating the substrate.

Second, a drop of the HE-CelCN solution is placed in the center of thesubstrate using a measuring pipette, followed by spin-coating whilecentrifuging at a rotation speed of 3000 rpm for 30 seconds. Theproduced film is immediately prebaked at 100° C. for 1 hour.

Third, the initially isotropic polymer film is irradiated with polarizedUV light having a wavelength λ below 365 nm to render it anisotropic,with either a positive or a negative dielectric. The irradiation time ismore than 5 seconds, and the intensity of UV light is about 5 mW/cm².

An embodiment of the light irradiating procedure utilizes a substrate, aphoto-alignment layer including a HE-CelCN on the substrate, a lamp forirradiating UV light over the photo-alignment layer, and a polarizer forpolarizing the light irradiated from the lamp.

The lamp (for example) is a Halogen (Hg) lamp. Light having an averagepower of 500 W is transmitted from a lens of the halogen lamp, polarizedby polarizer, and irradiated onto the photo-alignment layer at a powerof 5 mW/cm².

First irradiation is performed by vertically irradiating UV light on thesubstrate for 2˜10 minutes, and the polarization of UV light isperpendicular to the longitudinal direction of the substrate. Secondirradiation is performed by inclinedly irradiating UV light on thesubstrate in 45° C. for 5˜40 seconds, and the polarization of the UVlight is parallel with the incident light (P wave).

An LCD employing the alignment layer of the present invention comprisesa substrate having an alignment layer of HE-CelCN, and the othersubstrate having an alignment layer of polyimide(PI). The PI alignmentlayer is rubbed, so that the alignment direction thereof is determinedand is parallel with the longitudinal of the substrate. The abovesubstrates are laminated using spacers of 6.4 μm therebetween, andliquid crystal material of ZLI 4801-000 is injected therebetween. Thecell gap is 4 to 5 μm.

Reviewing the characteristics of the LCD, it could obtain a uniformalignment with a good quality even with the short irradiating time. Thealignment layer has a stronger anchoring energy compared with thealignment obtained from conventional photo-alignment materials.

The pretilt angle of alignment layer of HE-CelCN according to theirradiation time has been measured and the values thereof are as followsin Table 1, which shows the pretilt angle of the alignment layer isdetermined by the irradiation time.

TABLE 1 First Second Pretilt Irradiation Irradiation Angle Materials(min) (sec) (°) Hydroxyethyl 2 10 4 Cellulose 2 20 6 4-fluorocinnamate 240 8 Hydroxyethyl 10   5 3 Cellulose 10  10 5 5-methoxycinnamate

To estimate the thermostability of the CelCN, the quality of thealignment layer was checked using an electro-optical technique.Electro-optical response, in terms of cell transmittance ratio betweencrossed and parallel polarizers, anchoring energy and surface density ofthe alignment layer were each measured in a twisted nematic (TN) cellcontaining samples of the CelCN layers. The cell was heated to about100° C. and kept at this temperature for 4 hours. After cooling thesamples to room temperature, it was observed that the performancecharacteristics were maintained without change.

Among its other advantages, UV irradiation time is significantlyreduced. Whereas prior art photo-alignment techniques involved UVirradiation for anywhere from 5 to 10 minutes, this provides a methodwhich successfully achieves photo-alignment using UV irradiation inanywhere from about 0.5 seconds to one minute. The results are shown inthe following TABLE 2:

TABLE 2 Irradiation Time Tilt Thermostability Materials (sec) (°) (°)Polysiloxane 200 0 0 4-fluorocinnamate 1000  0 0 Polyvinyl 200 0Alignment 4-fluorocinnamate 500 0 broken Hydroxyethyl  30 1 14-fluorocinnamate  60 2 2

Preferred embodiments of the present invention will now be described infurther detail. It should be understood that these examples are intendedto be illustrative only and that the present invention is not limited tothe conditions, materials or devices recited therein.

EXAMPLE 1 Synthesis of 4-fluorocinnamic acid

A mixture of 0.1 mol 4-fluorobenzaldehyde, 0.15 mol malonic acid, and0.1 ml piperidine in 30 ml pyridine is boiled for 10 hours, cooled, andtreated with 150 ml HCl having a 10% concentration. The precipitate isfiltered and crystallized with ethanol. The yield of 4-fluorocinnamicacid is 68% and the melting point is 211° C.

The following compounds are synthesized in a similar manner:

-   -   2-fluoro cinnamic acid;    -   3-fluoro cinnamic acid;    -   3-chloro cinnamic acid;    -   4-chloro cinnamic acid;    -   2-methyl cinnamic acid;    -   4-phenyl cinnamic acid;    -   4-methoxy cinnamic acid;    -   4-pentoxy cinnamic acid;    -   4-heptyloxy cinnamic acid;    -   4-nonyloxy cinnamic acid;    -   4-(4-pentoxyphenyl)cinnamic acid;    -   4-trifluoromethoxy cinnamic acid;    -   4-trifluoromethyl cinnamic acid;    -   4-pentyl cinnamic acid; and    -   4-methoxy-3-fluorocinnamic acid.

EXAMPLE 2 Synthesis of HE-cellulose Cinnamate

A mixture of 0.05 mol cinnamoyl chloride (prepared from a cinnamic acidproduced in Example 1, an excess of thionyl chloride, and catalyticquantities of dimethyl formamide), 0.01 mol HE-cellulose, and 0.06 molpyridine in 20 ml nitrobenzene is heated for 24 hours at 80° C., cooled,and diluted with methanol. The reaction product is filtered, washed withmethanol and water, dried in a vacuum, and subsequently milled by avibrating mill. The yield of cellulose cinnamate is approximately 65% to92%. Thin layer chromatography (TLC) reveals there is no cinnamic acidin the reaction products.

The mechanism of the synthesis according to an embodiment of the presentinvention is as follows:

X₁ and X₂ are each selected from the group consisting of hydrogen,fluorine, chlorine, CN, NO₂, CH₃, OCH₃, CF₃, OCF₃

k=0˜1

Y is hydrogen, fluorine, chlorine, CN, NO₂, CF₃, OCF₃, C_(n)H_(2n+1),OC_(n)H_(2n+1), C_(n)H_(2n+1−x)F_(x), OC_(n)H_(2n+1−x)F_(x) (n=1˜10,x=1˜2n+1)

In addition, R includes a material selected from the group consisting ofOH, SH, OC_(n)H_(2n+1), COC_(n)H_(2n+1), OC_(n)H_(2n)OH,OCOC_(n)H_(2n+1), NHCOC_(n)H_(2n+1) (n=1˜10), or cinnamoyl derivativesincluding hydrogen, fluorine, chlorine, CN, NO₂, CH₃, OCH₃, CF₃, OCF₃,C_(n)H_(2n+1), OC_(n)H_(2n+1), C₆H₅, C₆H₄OC_(n)H_(2n+1),C_(n)H_(2n+1−x)F_(x) or OC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1).

Also, it is possible that the cinnamoyl derivative is

(X₁ and X₂ are each selected from the group consisting of hydrogen,fluorine, chlorine, CN, NO₂, CH₃, OCH₃, CF₃, OCF₃; k is 0 to 1; Y isselected from the group consisting of hydrogen, fluorine, chlorine,cyano, NO₂, CF₃, OCF₃, C_(n)H_(2n+1), OC_(n)H_(2n+1),C_(n)H_(2n+1−x)F_(x), OC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1), and hasa functional group as a spacer such as O, S, NH, OC_(h)H_(2h),OC_(h)H_(2h)O (h=1˜5) or the like between the main chain of thecellulose polymer and the cinnamoyl derivative.

As shown in FIG. 1, a liquid crystal display device comprises first andsecond substrates 100, 101, respectively, a thin film transistor (TFT)70 on the first substrate 100, a first alignment layer 50 formedentirely over the TFT 70 and first substrate 100, a second alignmentlayer 51 formed on second substrate 101, and a liquid crystal layer 90injected between the first and second substrates 100, 101.

First and/or second alignment layers 50, 51 include a pyranose orfuranose polymer, for example the HE-CelCN showed above. The HE-CelCNprovides good uniform alignment in a short irradiation time.

The pyranose and furanose polymers preferably comprise bothphoto-sensitive constituents and non-photo-sensitive constituents whichare composited in a specific ratio. It includes a spacer such as O, S,NH, OC_(h)H_(2h), OC_(h)H_(2h)O (h=1˜5) or the like between the mainchain of the polymer and photo-sensitive or non-photo-sensitiveconstituent.

The pyranose and furanose polymers can be composited with only oneconstituent from each of photo-sensitive and non-photo-sensitiveconstituents, or one or more different photo-sensitive and/ornon-photo-sensitive constituents.

When UV light is irradiated onto the first and/or second alignmentlayers at least once, the alignment direction and the pretilt angle aredetermined and alignment stability of the liquid crystal is achieved.

As the light used in the photo-alignment method, light in the UV rangeis preferable. It is not advantageous to use unpolarized light, linearlypolarized light, or partially polarized light.

Moreover, it is contemplated that only one substrate of the first andsecond substrates be photo-aligned using the above-described methodwhile the other substrate is not so treated. If both substrates arephoto-aligned, it is possible that the other substrate be treated withpolyamide or polyimide as the alignment material and that the alignmentbe accomplished by rubbing methods. It is also possible to use aphoto-sensitive material such as polyvinyl cinnamate (PVCN) orpolysiloxane cinnamate (PSCN) as the alignment material for the othersubstrate and accomplish the alignment using photo-alignment methods.

As to the nature of liquid crystal layer, it is possible to align thelong axes of the liquid crystal molecules parallel with the first andsecond substrates to produce a homogeneous alignment. It is alsopossible to align the long axes of the liquid crystal moleculesperpendicular to the first and second substrates to achieve ahomeotropic alignment. Moreover, it is possible to align the long axesof the liquid crystal molecules with a specific predetermined angle inrelation to the substrates, with a tilted alignment in relation to thesubstrates, with a twisted alignment in relation to the substrates, orin an alignment parallel to one substrate and perpendicular to the othersubstrate to provide a hybrid homogeneous-homeotropic alignment. It isthus essentially possible to apply any mode of alignment of the liquidcrystal molecules in relation to the substrates as may be desired, suchchoices being apparent to one of ordinary skill in the art.

Also, the first and/or second alignment layers can be divided into twoor more domains by creating different directional alignments of theliquid crystal molecules on each domain in relation to the direction ofthe substrates. Accordingly, a multi-domain LCD such as a 2-domain LCD,a 4-domain LCD, and so on can be obtained, wherein the liquid crystalmolecules in each domain are driven differently.

An LCD made in this way is characterized by excellent thermostability.It is thus possible to inject the liquid crystal into the liquid crystalcell at room temperature while preventing and avoiding any flowingeffect from being generated, as occurs in conventional techniques.Furthermore, the photo-alignment layer of the present inventionpossesses excellent photosensitivity, adhesion, and strong anchoringenergy. As a result, it is possible to align the liquid crystaleffectively and increase alignment stability of the liquid crystal.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the liquid crystal displaydevice of the present invention without departing from the spirit orscope of the invention. Thus, it is intended that the present inventioncovers the modifications and variations of this invention provided theycome within the scope of the appended claims and their equivalents.

1. A liquid crystal display device, comprising: first and secondsubstrates; a first alignment layer on the first substrate, wherein thefirst alignment layer includes

where the spacer S is sulfur, where m=10˜10,000, and where thefunctional group R includes photosensitive constituents which include acinnamoyl derivative and/or non-photosensitive constituents, wherein thecinnamoyl derivative is

(X1 and X2 are each selected from the group consisting of hydrogen,fluorine, chlorine, CN, NO2, CH3, OCH3, CF3, OCF3; k is 0 to 1; Y isselected from the group consisting of hydrogen, fluorine, chlorine,cyano, NO₂, CF₃, OCF₃, C_(n)H_(2n+1), OC_(n) H _(2n+1),C_(n)H_(2n+1−x)F_(x), OC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1)); and aliquid crystal layer between the first and second substrates.
 2. Theliquid crystal display device according to claim 1, further comprising asecond alignment layer on the second substrate.
 3. The liquid crystaldisplay device according to claim 2, wherein the second alignment layerincludes a material selected from the group consisting of a pyranosepolymer, a furanose polymer, polyvinyl cinnamate, polysiloxanecinnamate, polyvinyl alcohol, polyamide, polyimide, polyamic acid andsilicone dioxide.
 4. The liquid crystal display device according toclaim 2, wherein at least one of the first and second alignment layersis divided into at least two domains for driving liquid crystalmolecules in the liquid crystal layer differently on each domain.
 5. Theliquid crystal display device according to claim 1, wherein thenon-photo-sensitive constituents include a material selected from thegroup consisting of H, C_(n)H_(2n), C_(n)H_(2n+1), C_(n)H_(2n)OH,COC_(n)H_(2n+1), C_(n)H_(2n+1−x)F_(x), C_(n)H_(2n−(x−1))F_((x−1)),C_(n)H_(2n−(x−1))F_((x−1))OH, COC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1),and a combination thereof.
 6. A liquid crystal display device,comprising: first and second substrates; a first alignment layer on thefirst substrate, wherein the first alignment layer includes

where the spacer S is NH, where m=10˜10,000, and where the functionalgroup R includes photosensitive constituents which include a cinnamoylderivative and/or non-photosensitive constituents, wherein the cinnamoylderivative is

(X1 and X2 are each selected from the group consisting of hydrogen,fluorine, chlorine, CN, NO2, CH3, OCH3, CF3, OCF3; k is 0 to 1; Y isselected from the group consisting of hydrogen, fluorine, chlorine,cyano, NO₂, CF₃, OCF₃, C_(n)H_(2n+1), OC_(n)H_(2n+1),C_(n)H_(2n+1−x)F_(x), OC_(n)H₂H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1)); and aliquid crystal layer between the first and second substrates.
 7. Theliquid crystal display device according to claim 6, further comprising asecond alignment layer on the second substrate.
 8. The liquid crystaldisplay device according to claim 7, wherein the second alignment layerincludes a material selected from the group consisting of a pyranosepolymer, a furanose polymer, polyvinyl cinnamate, polysiloxanecinnamate, polyvinyl alcohol, polyamide, polyimide, polyamic acid andsilicone dioxide.
 9. The liquid crystal display device according toclaim 7, wherein at least one of the first and second alignment layersis divided into at least two domains for driving liquid crystalmolecules in the liquid crystal layer differently on each domain. 10.The liquid crystal display device according to claim 6, wherein thenon-photo-sensitive constituents include a material selected from thegroup consisting of H, C_(n)H_(2n), C_(n)H_(2n+1), C_(n)H_(2n)OH,COC_(n)H_(2n+1), C_(n)H_(2n+1−x)F_(x), C_(n)H_(2n−(x−1))F_((x−1)),C_(n)H_(2n−(x−1))F_(x−1)OH, COC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1),and a combination thereof.
 11. A liquid crystal display device,comprising: first and second substrates; a first alignment layer on thefirst substrate, wherein the first alignment layer includes

where the spacer S is OC_(h)H_(2h), where h=1˜5, where m=10˜10,000, andwhere the functional group R includes photosensitive constituents whichinclude a cinnamoyl derivative and/or non-photosensitive constituents,wherein the cinnamoyl derivative is

(X1 and X2 are each selected from the group consisting of hydrogen,fluorine, chlorine, CN, NO2, CH3, OCH3, CF3, OCF3; k is 0 to 1; Y isselected from the group consisting of hydrogen, fluorine, chlorine,cyano, NO₂, CF₃, OCF₃, C_(n)H_(2n+1), OC_(n)H_(2n+1),C_(n)H_(2n+1−x)F_(x), OCH_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1)); and aliquid crystal layer between the first and second substrates.
 12. Theliquid crystal display device according to claim 11, further comprisinga second alignment layer on the second substrate.
 13. The liquid crystaldisplay device according to claim 12, wherein the second alignment layerincludes a material selected from the group consisting of a pyranosepolymer, a furanose polymer, polyvinyl cinnamate, polysiloxanecinnamate, polyvinyl alcohol, polyamide, polyimide, polyamic acid andsilicone dioxide.
 14. The liquid crystal display device according toclaim 12, wherein at least one of the first and second alignment layersis divided into at least two domains for driving liquid crystalmolecules in the liquid crystal layer differently on each domain. 15.The liquid crystal display device according to claim 11, wherein thenon-photo-sensitive constituents include a material selected from thegroup consisting of H, OC_(n)H_(2n), OC_(n)H_(2n+1), COC_(n)H_(2n+1),C_(n)H_(2n)OH, OC_(n)H_(2n)OH, OCOC_(n)H_(2n+1), OC_(n)H_(2n+1−x)F_(x),OC_(n)H_(2n−(x−1))F_((x−1)), C_(n)H_(2n−(x−1))F_((x−1))OH,OC_(n)H_(2n−(x−1))F_(x−1)OH, COC_(n)H_(2n+1−x)F_(x),OCOC_(n)H_(2n+1−x)F_(x)(n=1˜10, x=1˜2n+1), and a combination thereof.16. A liquid crystal display device, comprising: first and secondsubstrates; a first alignment layer on the first substrate, wherein thefirst alignment layer includes

where the spacer S is OC_(h)H_(2h)O, where h=1˜5, where m=10˜10,000, andwhere the functional group R includes photosensitive constituents whichinclude a cinnamoyl derivative and/or non-photosensitive constituents,wherein the cinnamoyl derivative is

(X1 and X2 are each selected from the group consisting of hydrogen,fluorine, chlorine, CN, NO2, CH3, OCH3, CF3, OCF3; k is 0 to 1; Y isselected from the group consisting of hydrogen, fluorine, chlorine,cyano, NO₂, CF₃, OCF₃, C_(n)H_(2n+1), OC_(n)H_(2n+1),C_(n)H_(2n+1−x)F_(x), OC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1)); and aliquid crystal layer between the first and second substrates.
 17. Theliquid crystal display device according to claim 16, further comprisinga second alignment layer on the second substrate.
 18. The liquid crystaldisplay device according to claim 17, wherein the second alignment layerincludes a material selected from the group consisting of a pyranosepolymer, a furanose polymer, polyvinyl cinnamate, polysiloxanecinnamate, polyvinyl alcohol, polyamide, polyimide, polyamic acid andsilicone dioxide.
 19. The liquid crystal display device according toclaim 17, wherein at least one of the first and second alignment layersis divided into at least two domains for driving liquid crystalmolecules in the liquid crystal layer differently on each domain. 20.The liquid crystal display device according to claim 16, wherein thenon-photo-sensitive constituents include a material selected from thegroup consisting of H, C_(n)H_(2n), C_(n)H_(2n+1), C_(n)H_(2n)OH,COC_(n)H_(2n+1), C_(n)H_(2n+1−x)F_(x), C_(n)H_(2n−(x−1))F_((x−1)),C_(n)H_(2n−(x−1))F_(x−1)OH, COC_(n)H_(2n+1−x)F_(x) (n=1˜10, x=1˜2n+1),and a combination thereof.